pacpl on its own is a script which will only run from the command line.
There are graphical front ends for it, but none of them appear to be
in the standard repositories - and anyway, they all appear to be KDE
only, which isn't a problem if you're running Kubuntu or want to install
all the KDE libraries to run them under Gnome.

As an alternative, you could try Sound Converter, available at
http://www.getdeb.net/software/soundconverter

I've used this in the past and it's OK, but not as powerful as pacpl as
far as I can see.